1. Field of the Invention
The present invention relates to automotive engines and more specifically to an arrangement which reduces vibration produced by sudden fluctuations in the engine output torque.
2. Description of the Prior Art
In previously proposed engine torque output control arrangements, the torque fluctuations have been sensed at the crank shaft and in response to this the amount of current which passes through a field coil of an alternator associated with the engine, has been varied in a manner to vary the reverse torque which is applied to the engine crank shaft in an attempt to reduce the vibration producing effect of the output torque fluctuations.
In this type of arrangement, the amount of current which flows through the field coil is related to the level of the voltage which is produced. However, with this arrangement as the variation in the inductance component of the alternator field occurs after a finite delay, it has been very difficult to actually establish the appropriate voltage and adequately control the torque fluctuations.
Another proposal disclosed in JP-A No. 61-20333 has made use of a generator/motor arrangement which is directly connected to the engine crankshaft. In this arrangement the angular speed of the crankshaft has been sensed and the direct current (DC) supplied from the battery is converted into a multi-phase alternating current (AC) and supplied to the armature coil of the generator/motor device. In the armature coil the alternating current is converted to direct current and used to charge the battery. During this process, in the event that the angular speed of the crank shaft is sensed as being less than a predetermined reference value, the phase of the multi-phase current which is supplied to the armature coil is advance in accordance with the amount of difference between the instant angular speed of the crank shaft and the above mentioned reference value. On the other hand, in the event that the angular speed of the crank shaft is found to be greater than the reference value, the supply of multi-phase alternating current to the armature coil is controlled by a shut-off device.
This arrangement is such that while sudden strong reversals in torque can be controlled, its effect is limited to situations wherein momentary increases in torque occur. Accordingly, in the case of a misfire wherein a momentary reduction in torque takes place, adequate control of the fluctuation cannot be expected and as a result, vibration containing a given frequency which tends to have a disturbing influence on the passengers of the vehicle, tends to transmitted to the vehicle chassis.